1. The Field of the Invention
The present invention relates to analyzing signals between a host and a device by tapping the bus. More particularly, embodiments of the invention relate to detecting the operating voltages of the device while tapping the bus between the host and the device.
2. The Relevant Technology
Protocol Analyzers are devices that help diagnose and detect problems that occur on networks. Protocol analyzers can also be used on buses that exist between a host and a device for similar purpose. Typically, protocol analyzers view traffic on the network or over a bus or other connection as it occurs. As the data is being monitored, the protocol analyzer may detect a problem or some defined condition. At this point, the analyzer triggers and captures the data present on the network or occurring on the bus. The range of data captured can depend on the size of the analyzer's buffer. The analyzer can also be configured such that the captured data represents data that occurred before the triggering event, after the triggering event, and/or both before and after the triggering event. In addition, the data can also be captured without a triggering event. Rather, data can be captured until the buffer is full. In effect, the capture is a snapshot of the data that was present on the network around the time that a problem occurred. The captured data can then be analyzed to help resolve many problems and improve communications on the network or between a host and a device.
Some protocols, however, are difficult to implement in analyzers. SD (Secure Digital Cards), SDIO (SD Input/Output Cards), MMC (Multimedia Cards) and CE-ATA (Consumer Electronics-Advanced Technology Attachment) are examples of protocols that are difficult to analyze. Some of the reasons are related to the physical sizes of devices that use SD, SDIO, MMC or CE-ATA. Other reasons are related to the cost. CE-ATA connectors, for example, have a limited number of insertion cycles. Because protocol analyzers are repeatedly connected and disconnected, cost can become a significant issue when analyzing CE-ATA. In addition, many consumer devices do not operate at the same voltage levels. This can complicate the issue of connecting a system to a protocol analyzer when the voltage levels are not known beforehand.